Just to say thank you for sharing the codes. I did it on my X2 with code 1 only for now.
I am tempted to do the option 3 later. I need to make sure that the LED bulbs I put are not too bright for braking light and blind some people behind.
Like mentioned by someone above, I was not able to find the steps 6 and 7 in code 1 (Mapping_Nebelschlussl_L_PWM1 and Mapping_Nebelschlussl_R_PWM1). It worked without it anyway.
Also, I was about to buy the switch from Europe, but I found out that we can just remove 3 plastic tabs in another post and also this video (at 5:00):
It doesn't have the icon on the button, but it saves $100 .